1. Field of the Invention
The present invention relates in general to integrated analog/digital television receivers and in particular to a low cost method and device of providing a digital television receiver module in an existing analog television receiver.
2. Description of the Prior Art
Digital television services are presently being provided along with analog television services. During the time period of changeover from analog to digital it is necessary to have televisions which are able to operate in both the analog and digital environment.
The introduction of these digital television (xe2x80x9cDTVxe2x80x9d) services presents architecture issues to the design of integrated digital/analog TV products. Since the initial integrated digital/analog television production volume is low, it does not make commercial sense to alter existing analog television components to accommodate functional integration of DTV components. This is because conventional analog television has been on the cost optimization process for many years and the fundamental analog architecture development has been following the functional integration path. More and more digital processing technologies have gradually replaced analog techniques for better performance and featuring and the analog functional integration is on the path toward a single IC execution with tightly coupled functionality and cross-sharing of processing blocks. While this approach enables the continued cost optimization of a conventional analog television set, the integration of DTV with analog TV poses a significant cost penalty. DTV employs compression-based techniques and it does not share much commonality with analog signal processing. To fully integrate DTV with conventional analog TV functionality based on existing analog chassis requires modifications to the analog chassis that are expensive. If the analog chassis is not modified, then in order to integrate DTV with the analog TV and have a high quality DTV signal, duplicate circuitry is needed so the output of the DTV module can be supplied directly to the display, thereby bypassing the analog chassis.
FIG. 1 shows a television 4 which includes an analog chassis 10 and a picture-in-picture (PIP) module 20. The traditional analog chassis 10 is an integrated circuit with a limited number of inputs and outputs including i) RF in 3 ii) the AV jack panel 2 attached directly to the analog chassis comprising AV1 in and AV2 in, iii) the host controller 19 inputs and outputs for control of all modules within the analog chassis 10 and PIP module 20, vi) the output to display 5, and vii) the inputs 11 and outputs 12 associated with the PIP functionality (xe2x80x9cPIP interfacexe2x80x9d). Included within the analog chassis 10 is a tuner 15, an analog decoder 16, a multiplexer 18 and picture improvement circuitry 17. In order to incorporate the DTV module 30 in the present integrated analog/DTV receivers the DTV module 30 includes duplicate picture improvement circuitry 38 and the signal is multiplexed through multiplexer 40 on the output of the analog chassis 10 so that redesign of the analog chassis 10 is not necessary. Because the duplication of the picture improvement circuit is so expensive, many times this duplication is not even included in the design and the un-improved DTV signal at the output of the digital decoder 37 is provided directly to the display 5.
It is an object of the present invention to provide a low cost digital/analog television which does not necessitate redesigning the analog chassis and also enables the use of the same picture improvement circuitry in the analog chassis for the DTV signal. This object is achieved by providing a switched signal to the PIP interface of the analog chassis.
It is another object of the invention to provide a switched digital PIP input signal to the analog chassis, while preserving the same user experience with respect to the analog PIP. Thus digital PIP is an added feature without requiring the user to learn to operate additional keys on the remote control to turn on the digital PIP.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.